Many of the bolded characters in the characterization above are apomorphies of subsets of streptophytes along the lineage leading to the embryophytes, not apomorphies of crown-group embryophytes per se.

All groups below are crown groups, nearly all are extant. Characters mentioned are those of the immediate common ancestor of the group, [] contains explanatory material, () features common in clade, exact status unclear.

Age. The age of this node was estimated to be (94-)89(-85) or (80-)74(-68) m.y., Bayesian relaxed clock estimates to 96 m.y. (Hengchang Wang et al. 2009), while Argout et al. (2010) give a date for this clade (or that of a bigger clade, one perhaps including the common ancestor of all malvids) of only ca 59 m.y. (see also Xue et al. 2012), which has to be a major underestimate. A suggestion by Zhang et al. (2012) is for an age of (82-)73(-60) m.y., while Magallón and Castillo (2009) estimated an age of ca 92 m.y. and Naumann et al. (2013) ages of around 89.2-80.8 m.y. for this clade.

Note: Possible apomorphies are in bold. However, the actual level at which many of these features, particularly the more cryptic ones, should be assigned
is unclear. This is partly because many characters show considerable homoplasy, in addition, basic information for all too many is very incomplete, frequently coming from taxa well embedded in the clade of interest and so making the position of any putative apomorphy uncertain. Then there is the not-so-trivial issue of how ancestral states are reconstructed (see above).

Malvales can often be recognised by their
spiral, pulvinate leaves that often have palmate venation, or at least a pair of lateral veins leaving from the very base of the blade; stellate or
fasciculate hairs and their derivatives are common. The bark is often very fibrous and tough because of the stratified phloem. The calyx is sometimes valvate, the corolla
often contorted, the stamens usually numerous, the capsule sometimes muricate or spiny, and the seeds or inside of the carpel walls are
sometimes conspicuously hairy.

Evolution.Divergence & Distribution. Dating the separation of clades within this group is of considerable interest given the distributions of many of the families. That aside, as Kubitzki and Chase (2002: Table 1) show, the evolution of cyclopropenoid fatty acids and many other features common in the order is difficult to understand.

The androecium is possibly basically oligomerous, and the earliest initiated or innermost members are oppositisepalous with centrifugal or lateral polyandry. Starchy endosperm may be an apomorphy for the group.

Some general information, esp. carpel
orientation, is taken from from Nandi (1998a, b) and Kubitzki and Chase (2002); for wood anatomy, see i.a. den Outer and Vooren (1980) and den Outer and Schütz (1981).

Phylogeny For a summary of phylogenetic studies, see Le Péchon and Gigord (2014). Some clades within Malvales are quite well established, but relationships between them, as well as the position of one or two families, remain unclear. Fay et al. (1998a) and Bayer et al. (1999) discuss general relationships. These may be represented as [Muntingiaceae [[Bixaceae + Malvaceae] [[Thymelaeaceae + Sphaerosepalaceae] [Neuradaceae [Sarcolaenaceae [Dipterocarpaceae + Cistaceae]]]]]], but few of these relationships have much support, even after successive weighting (Bayer et al. 1999). Neuradaceae may be sister to the rest of the order (see also Soltis et al. 2007a). Molecular data (Fay et al. 1998a) place Diegodendron close to Bixa in particular. Although Bixaceae are expanded here, it has also been suggested that Cochlospermum and relatives are close to Diegodendron and Sphaerosepalaceae, less to Bixa (Johnson-Fulton & Watson 2008). The relationships of Sphaerosepalaceae within Malvales are unclear; in Bayer et al. (1999) they are weakly associated with Thymelaeaceae and in Alverson et al. (1998) with Bixaceae and Cochlospermaceae. The relationships within the clade that includes Sarcolaenaceae, Dipterocarpaceae and Cistaceae are also uncertain (Ducoussu et al. 2004). See also Soltis et al. (2011) for relationships; these are somewhat different from those discussed above, but sampling is poor.

Relationships of Cytinaceae with Malvales had been suggested (Nickrent 2002), and these appeared in all analyses in Nickrent et al. (2004). Since the only Malvales included in Nickrent et al. (2004) were Cistaceae and Malvaceae, the placement of Cytinaceae remained somewhat provisional. However, with much better sampling Nickrent (2007: nuclear small-subunit [SSU] r-DNA was the nuclear gene used) found that Cytinaceae are sister to the poorly-known Muntingiaceae with moderate (maximum likelihood) to strong (maximum parsimony) support. Both Cytinaceae and other Malvales have exotegmic seeds, and aspects of the perianth of Cytinaceae and Malvaceae can perhaps be compared. Apodanthaceae, here included in Cucurbitales (see Filipowicz & Renner 2010), are also somewhat similar morphologically to Malvales (Nickrent et al. 2004).

Previous Relationships. Elaeocarpaceae, previously usually included in (Cronquist 1981) or near Malvales, are here placed unambiguously - if somewhat unexpectedly - in Oxalidales. Most Malvales as delimited here are included
in Takhtajan's (1997) Malvanae; the core of Malvales in the past was the families here all included in Malvaceae.

Neuradaceae are rather small herbaceous or subwoody plants of warm Saharo-Indian desert areas with small, toothed, exstipulate leaves and white flowers the petals of which dry a distinctive color; the petals are spreading, there are ten stamens and usually 10 separate and erect styles, and the fruits are spiny.

Chemistry, Morphology, etc. The vascular bundles have a mucilaginous sheath. The plant probably lacks stipules, the stipule-like structures that are sometimes seen in fact being prophylls (Bayer 2002); the presence/absence of stipules should be confirmed. The basically cymose inflorescence/plant construction with paired but unequal leaves makes things complicated.

There appears to be no epicalyx, although the outside of the ovary may have spines which become conspicuous in fruit; these develop centrifugally (Ronse DeCraene & Smets 1995d). The flowers of Grielium are obliquely monosymmetric, some of the carpels on one side of the flower being reduced and non-functional (Murbeck 1916). The corolla of members of Neuradaceae changes colour on drying, as in some Malvaceae (Airy Shaw 1966) - see Huber (1993a). There is sometimes a second, reduced ovule in the carpels (Murbeck 1916). Goldberg (1986). The seed begins to germinate while still inside the fruit (e.g. Murbeck 1916), hence reports (Takhtajan 1997) that the carpels dehisce ventrally.

For general information, see Murbeck (1916) and Bayer (2002), and for pollen, see Polevova et al. (2010); the family needs work.

Previous Relationships. Neuradaceae have previously placed been elsewhere, as in
Rosales in Cronquist (1981) and Takhtajan (1997); Hutchinson (1973) and Corner (1976)
included it in the Rosaceae, and the floral anatomy of the two is similar (Ronse
Decraene & Smets 1995b), although Corner (1976) noted that the seed coat anatomy appeared to be different.

Thymelaeaceae are recognisable by their very fibrous
bark and entire, exstipulate often opposite leaves which frequently have rather
close, parallel venation and leave prominent raised scars on the stem after they fall off; the indumentum is of unicellular hairs and is often silky-adpressed. In many taxa, the twigs are notably
flexible and the plants smell unpleasantly. The flowers are quite often in heads, and the hypanthium is often
long; any corolla lobes are usually at most small. The plants are often toxic.

Economic Importance. A number of taxa scattered through the family produce gaharu or agarwood. This is developed from the heartwood often after wounding and perhaps also after infection by fungi; gaharu is much esteemed as source of incense and medicines, and some species that produce it have been decimated in the wild (Eurlings & Gravendeel 2005).

At least some Thymelaeoideae have a lignified, torus-bearing, pit membrane (Coleman et al. 2004; Dute et al. 2011 and references). Carlquist (2013) recorded interxylary phloem from several members of the family. The petiole anatomy of Gonystylus needs to be confirmed; the bundle is perhaps unlikely to be arcuate.

Floral morphology in the family is poorly understood. The vasculature of the perianth in Thymelaeaceae was studied by Heinig (1951). The vascular bundles supplying the structures inside the calyx, whether paired and more or less opposite the sepals or single and in the petaline position, came from lateral branches of the sepal vasculature; equating these structures with stipules seems unlikely. Dicranolepis (Octolepidoideae: Africa) has large "petals" that are variable in number but paired and opposite the petals, and they are sometimes serrate or laciniate. Other taxa have single structures alternating with the lobes of the perianth tube, while in Lachnaea there are paired structures in the perianth tube borne below the instertion of the two whorls of stamens (Herber 2002b). Here I have been conservative, calling the major tubular structure a perianth, I am agnostic about the occurrence of petals and also whether a hypanthium in the strict sense is present or not. Synandrodaphne lacks a floral tube.

The pollen of many Thymelaeoideae is similar to that of Euphorbiaceae-Crotonoideae. The micropyle of Gnidia is zig-zag. Eckardt (1937) discussed gynoecial variation in members of Thymelaeoideae. Spichiger et al. (2004) showed Daphne alpina as having a straight (and sessile) ovule.

The testa of Tepuianthus is about 6 cells thick and unlignified, then there is a layer of lignified palisade cells, the exotegmen, and immediately underneath apparently a layer of low, lignified cells, i.e., the seed coat is similar to that of other members of the family. Reports of a small embryo (Maguire & Steyermark 1981) need to be confirmed. The base of the lamina joins the petiole on the adaxial side, and so the lamina
is almost peltate. Illustrations
in Maguire and Steyermark (1981) suggest that there are colleters at the base
of the calyx. See Roth and Lindorf (1990) for anatomy of the genus.

Phylogeny. For the phylogeny of the family, see van der Bank et al. (2002). They found the following set of relationships [Gilgiodaphne (= Synandrodaphne), Gonystyloideae [Aquilarioideae + Thymelaeoideae]]. These relationships, other than the position of Gilgiodaphne, were well supported: genera like Tepuia and Octolepis were not included, while Gnidia was highly polyphyletic (see also the much more detailed study of Beaumont et al. 2009). Motsi et al. (2010) looked at relationships around Pimelea.

The inclusion of Tepuianthus in this clade makes eminent morphological sense (Wurdack & Horn 2001; Horn & Wurdack, ms.). It has a number of apomorphies of other Thymelaeaceae, while the features in which it differs from them are mostly plesiomorphies, i.e., they are similarities to other Malvales. Tepuianthus has both a well-developed calyx and corolla and also scales outside the androecium, perhaps suggesting that the corolla scales of Gonystylus, and perhaps those of the rest of the family, are homologous with these glandular scales. Furthermore, although it is described as having three separate styles, the stigmas being bilobed or not, these "styles" may be similar to similar processes on top of the ovary in Gonystyloideae, which are called parastyles and are associated with the styles proper. Distinctive epidermal columns in the palisade mesophyll of the leaf of Tepuianthus are found in other Thymelaeaceae such as Solmsia, and its resin cavities may be compared with the secretory cells of Octolepidoideae. The bark of Tepuianthus is described as being bitter, while Thymelaeoideae are well known for often being rather poisonous, unfortunately, the chemistry of Octolepidoideae is poorly known. Finally, the well developed parallel venation of Tepuianthus is very like that of other Thymelaeaceae, and Solmsia (New Caledonia: Octolepidoideae) is vegetatively remarkably similar to Tepuianthus down to details of the base and mucronate apex of the lamina.

Classification. On hold at present. The old Aquilarioideae are monogeneric and where the monogeneric Gilgiodaphnoideae (van der Bank et al. 2002) are to go is unclear. Daphne is probably to include Wikstroemia (Halda 2001); many generic limits will need reconsideration because of the fragmentation of Gnidia, yet Gnidia s.l. is not necessarily "maximally stable" given the poor support for the clade it represents (c.f. Beaumont et al. 2009: 413). For general information, see Zachary Rogers's A World Checklist of Thymelaeaceae (2009 onwards).

Previous Relationships. The pollen of many Thymelaeaceae-Thymelaeoideae is similar to that of Euphorbiaceae-Crotonoideae, and the
chemistry is also similar to that of Euphorbiaceae, including the presence of
phorbol ester diterpenes (Seigler 1994); Takhtajan (1997) placed Thymelaeales immediately after Euphorbiales. Because Microsemma (= Lethedon) has cyclopentenoid cyanogenic
glycosides, Spencer and Seigler (1985) suggested that it
should be placed in Flacourtiaceae (see Achariaceae here). Thymelaeaceae were included in Myrtales by Cronquist (1981).

Sphaerosepalaceae are a small family, but with a great deal of variation. The stipules are broad, intrapetiolar, and more or less encircle the stem. The flowers are usually four merous and the sepals are imbricate in pairs; the carpels are single seeded.

Chemistry, Morphology, etc. Secretory cavities are abundant, and the carpels produce an exudate when
cut. The rays are not storied (den Outer &
Schütz 1981), and Jansen et al. (2000a) did not find vestured pits (c.f. den
Outer & Schütz 1981). Takhtajan (1997) described the
stipules as being extrapetiolar and the endosperm as being copious.

The lateral sepal bundles are commissural, as in Thymelaeaceae. There are androecial trunk bundles opposite the petals. The apparently terminal style may be modified from the gynobasic condition (Horn 2004).

For more
information, see Capuron (1962), Huard (1965), Bayer (2002) and Horn (2004).

Synonymy: Rhopalocarpaceae Takhtajan

Age. The age for a clade that includes Malvaceae, Cistaceae, Bixaceae and Cytinaceae is around (92.5-)72.1(-51.9) m.y. in Naumann et al. (2013); relationships in this clade are [Malvaceae (ca 61.9 m.y.) [Bixaceae + Cistaceae (ca 52.4 m.y.)]].

Evolution.Ecology & Physiology. The bixoid chalazal plug forms a water gap through which water enters the hard seeds, so causing the breaking of the physical dormancy of the seeds (Baskin et al. 2000).

Phylogeny. Bixaceae + Cistaceae may form another group: leaf
teeth with a single vein proceeding to opaque deciduous apex; embryo long, cotyledons thin, curved or folded, radicle
short, stout. Molecular phylogenies are largely silent about the grouping above, but suggest that this clade will not be supported.

The spiral, stipulate leaves of Cochlospermum are palmately lobed. The flowers are large, more or less monosymmetric, usually yellow, and
there are many stamens with porose anthers. The fruit is distinctive: it is a septicidal capsule the endocarp of which separates from the mesocarp, and the seeds are many, hairy, and curved. The plants often have a yellowish resiny
exudate.

Bixa has peltate hairs, leaves with palmate venation
and stipules ensheathing the bud; there is red or orange exudate. The large flowers have porose anthers folded
horizontally, parietal placentation, and the seeds have a pulpy testa; the glands at the bases of the sepals are conspicuous.

Diegodendron has two-ranked, rather short-petiolate and
punctate leaves with pinnate venation and deciduous stipules completely surrounding the stem; there are peltate glands. The flowers are quite large and are borne in a terminal panicle and the style is gynobasic. The plant is described as being aromatic.

Economic Importance. The orange colouring of Bixa orellana, annatto, is used as a food colouring, e.g. for margarine.

Chemistry, Morphology, etc. In Cochlospermum vitiifolium
the median sepal is abaxial, there are no bracteoles, and the sepals are of
unequal size (or three "true" sepals + two bracteoles?). Flowers of Cochlospermum are monosymmetric in bud, and the floral
vasculature is monosymmetric. The
androecium has five or six bundles, and development is centrifugal. Carpel orientation needs to be checked if
the flower is inverted. There is no obvious nectary. Amoreuxia has obliquely (?tranversely) monosymmetric flowers, the positionally "upper" stamens being much shorter than the lower ones and differently coloured; the four "upper" petals are bicolored.

The gums of Cochlospermum
and those of Sterculia (Malvaceae-Sterculioideae) are similar, both containing acetylated acidic
polysaccharides.

See Keating
(1970, 1972) and Poppendieck (1980, 2002) for general details and Dathan and Singh (1972) and Ronse Decraene (1989b) for embryology and floral development of Bixa and Cochlospermum.

For general information on Bixa, see Poppendieck (2002). The wood anatomy of Diegodendron is very like that of
Sphaerosepalaceae (Dickison 1988), but the genus is otherwise poorly known (see also Bayer 2002).

Classification. Although Diegodendron does seem morphologically rather different from the other two groups (Kubitzki & Chase 2002, Table 1), nevertheless, all three have much in common; the absence of a bixoid chalazal plug in Diegodendron is probably because the fruit is indehiscent. Cochlospermaceae and Diegodendraceae were provisionally placed in Bixaceae s.l. (see A.P.G. II 2003) and later combined (APG III 2009).

Previous Relationships.Diegodendron was included in
Ochnaceae by Cronquist (1981), but excluded by Amaral (1991); Diegodendraceae were
placed in Malvales by Takhtajan (1997).

[Cistaceae + Sarcolaenaceae +
Dipterocarpaceae]: ectomycorrhizae +; tracheids +; ellagic acid +; plant with secretory canals; K with the two outer members often different from the rest, imbricate/quincuncial; filaments not articulated; ovules both anatropous and straight; exotegmen curved inwards in chalazal region, hypostase plug with
core and annulus; endosperm starchy.

Age. Ages for this node offered by Wikström et al. (2001) are (41-)39(-37) or (25-)23(-21) m.y., the ages in Bell et al. (2010) are (56-)46, 42(-28) m.y. and those in Guzmán and Vargas (2009) are (27.6-)24(-23.0) m.y., but these must be underestimates; see below for ages of Dipterocarpaceae and [Sarcolaenaceae + Dipterocarpaceae].

Evolution.Ecology & Physiology. Ectomycorrhizae (ECM) are common in this clade (e.g. Appanah 1998; Ducoussu et al. 2004), and with some 915 species it may be the second largest ECM clade in angiosperms.

Phylogeny. This grouping is strongly supported in molecular studies, albeit the sampling is still poor; indeed, both Sarcolaenaceae and Cistaceae may be embedded within Dipterocarpaceae as currently circumscribed (Kubitzki & Chase 2002; Ducousso et al. 2004). Fancy the nomenclatural brouhaha that will result if this is confirmed! Nandi (1998b) noted several similarities between Cistaceae and Sarcolaenaceae (hollow style, stigma morphology, carpel number and indumentum). Future morphological studies may well strengthen the characterisation of the whole clade, but relationships within it are unclear.

7/165: Helianthemum (80-110), Crocanthemum (24), Cistus (18). Esp. the Mediterranean
region, also Eurasia, North Africa (inc. the Horn of Africa), North America, and southern South America.

Age. The age for this node was estimated at around (14.7-)11.8(-8.4) m.y. (Guzmán & Vargas 2009; see also Vargas et al. 2014).

Synonymy: Helianthemaceae G. Meyer

Cistaceae are aromatic shrubs growing in open, sunny areas often on a sandy or chalky substrate. They often have opposite
leaves with broad, even connate bases. The inner three sepals are sometimes
described as being contorted, rather, the aestivation is extreme-quincuncial,
the two outer sepals being much smaller than the others. The petals are free and are contorted in a direction opposite to that of the three large sepals and are crumpled when in bud; there are numerous stamens that are often sensitive to touch.

Evolution.Ecology & Physiology.Cistus in particular dominates in the shrubby Maquis vegetation in the Medierranean region; Maquis may be transitional to Quercus- and Pinus-dominated vegetation (Comandini et al. 2006). It has been suggested that there has been movement of the family from the Old World to the New Word and back within the last 12 m.y. (Vargas et al. 2014), and much diversification may have occurred within the time that Mediterranean vegetation became established, within the last 7 m.y. or so.

Pollination Biology & Seed Dispersal. Many Cistaceae have stamens that are sensitive to touch, moving and dusting the insect with pollen when it disturbs them.

For mucilages in the seeds of Cistaceae and their possible functions, see Yang et al. (2012) and Engelbrecht et al. (2014).

Bacterial/Fungal Associations. Endomycorrhizae as well as ECM have been reported from Cistaceae (Comandini 2006; de Vega et al. 2010, 2011), and the latter are also to be found in the tissue of Cytinus (Cytinaceae) a parasite of this family in the Mediterranean region (de Vega et al. 2010, 2011, c.f. Brundrett 2011). Hudsonia from eastern Canada, ECM plants, have lateral roots only ca 59 µm across, comparable with the hair roots of Ericaceae with their ericoid mycorrhizae, modified ECM (Massicotte et al. 2010).

Chemistry, Morphology, etc. For the absence of root hairs, at least in seedlings, and the fungal associations of the plant, see references in Arrington and Kubitzki (2002); Dickie et al. (2004) also mention ECM in Helianthemum. Kapil and Maheshwari (1965) note fungal hyphae in the ovules which, however, do not infect the seed. Wood rays are uniseriate
and xylem parenchyma is almost absent (Keating 1966).

Corolla initiation in Cistaceae tends to be retarded (Nandi 1998b), although it is not retarded in Dipterocarpaceae (Kocyan 2005). The androecium has ten vascular bundles,
each bundle of the oppositisepalous whorl supplies a group of stamens while the traces
of the inner whorl usually supply a single stamen only; Saunders (1936) suggested that in Cistus there are five oppositipetalous groups. At least some Cistaceae have starchy pollen grains. The embryo is green (1 record) or white
(Nandi 1998a). Fumana has n = 16 (Guzmán & Vargas 2009).

For floral diagrams, see Eichler (1878), for floral development, see Nandi (1998b), for ovule and seed anatomy, Nandi (1998a), for general information, Arrington and Kubitzki (2002, revised in Arrington 2004). For more information on the web, see R. Page's Cistus and Halimium website.

Phylogeny.Fumana and Lechea are successively sister to the remainder of the family with 100% posterior probabilities but mediocre maximum parsimony support (Guzmán & Vargas 2009); the former in particular has a number of features that are plesiomorphic in the family (Arrington 2004). Both have only three petals, and Fumana, alone in the family, has staminodes. Tor the phylogeny of Cistus, see Guzmán and Vargas (2005); the relationships of Halimium and Cistus are intertwined (Civeyrel et al. 2011).

Previous relationships. Takhtajan's Cistales included
Cistaceae, Bixaceae and Cochlospermaceae. Corner (1976 1: 97) described Cistaceae as being "little more than
variations on a single generic theme", and noted similarities between the three
families mentioned.

Age. Ducousso et al. (2004) suggest that Dipterocarpaceae and Sarcolaenaceae had a common ancestor some 88 m.y.a., that is, prior to the split of India and Madagascar; ages suggested by Wikström et al. (2001) are only (30-)28(-26) or (16-)14(-12) m.y.a..

The flowers, which have a massive "involucre" and sometimes also an enclosing bract (?bracteole), and an extrastaminal disc, are distinctive. The underside of the lamina of Sarcolaena has parallel lines. The hairs are stellate.

Evolution.Divergence & Distribution. Fossil pollen of Sarcolaenaceae is known from the Caenozoic of South Africa (Coetzee & Muller 1984).

Chemistry, Morphology, etc. Sarcolaenaceae are the family with a "fleshy outer tunic". For details of cyclopropenoid fatty acid distribution, see Gaydou and Ramanoelina (1983), for ECM, see Ducousso et al. (2004), and for pollen, see Polevova et al. (2010) and references.

13/650: Shorea (360), Hopea (105: these two
should perhaps be merged), Dipterocarpus (70), Vatica
(60). Seychelles, Sri Lanka, India, South East Asia
to New Guinea, but mostly W. Malesian, often dominating in mixed-species stands (map: above, area in red). [Photo - Flower, Fruit.]

Dipterocarpaceae are trees that may be recognised by their often
two-ranked, coriaceous leaves with strong, parallel, if not particularly close,
secondary veins and scalariform tertiaries; the hairs are often fasciculate or
stellate. The inflorescences are often
distinctively monochasial, and the small flowers are pointed in bud and have a
conspicuously contorted corolla. Distinctive fruits with
strongly accrescent but often unequal sepals surrounding single-seeded nuts are
common in the family, but there are other fruit types.

Evolution.Divergence & Distribution. Fossil wood identified as Dipterocarpoideae has been found in east Africa and also in the Horn of Africa (Ashton 1982); there are no extant Dipterocarpoideae on the continent. Substantial resin deposits in Gujarat, western India, are from Dipterocarpoideae and have been dated to the Ypresian (Early Eocene), some 52-50 m.y.a.; insects in the amber the resin formed do not suggest any particular isolation of the continent (Rust 2010). These deposits contain bicadinanes, the breakdown products of the dammar resin of dipterocarps, and they have been associated with dipterocarp ascomycete ECM (Beimforde et al. 2011). Resin deposits are also found in West Malesia-South East Asia rather later in the Caenozoic.

This may suggest an origin or early occurrence of the family in India and later dispersal to South East Asia-Malesia after contact of the two was established ca 50 m.y.a. (Dutta et al. 2011). A similar scenario was suggested by Ashton et al. (1988), who also proposed that the distinctive masting behaviour of the family (see below) evolved in Dipterocarpaceae in the seasonal tropics. Such dates are more likely than the 41 m.y.a. (Eocene-Bartonian) or much younger ages suggested above. One the other hand, that Diperocarpaceae grew on Gondwana some 135 m.y.a. (Moyersoen 2006) seems unlikely.

Ecology & Physiology. ECM Dipterocarpaceae are large trees that are often dominant in l.t.r.f. from India and Sri Lanka to West Malesia, where they grow both in seasonal and everwet forests (Alexander 1989). In Sri Lanka four species of Stemonopurus are recorded as being individually dominant in montane forest - an unusual habitat for the family - where they represented 33.2-74.5% of the basal area (Greller et al. 1987). Monotes in Africa is also often described as being locally abundant in the woodland to savanna habitats it frequents (White 1983).

Dipterocarpaceae are the most diverse tree family in the West Malesian l.t.r.f. (Gentry 1988), and Shorea is about the most diverse genus there (Davies et al. 2005). In the West Malesian forests Dryobalanops aromatica and Shorea albida in particular may form very extensive and close to monodominant stands (e.g. Connell & Lowman 1989). In Lambir forest, Sarawak, Dipterocarpaceae make up only 7.4% of the species but 41.6% of the basal area (918.4 m2); the figures for Shorea alone are 4.7%, 21%, and 467.8 m2, Dryobalanops aromatica and Dipterocarpus globosus between them accounted for 13.2% of the basal area, and seven dipterocarps (out of the ten most dominant species) accounting for 23.1% (Lee et al. 2002; Davies et al. 2005; also Alexander 1989). Both Dryobalanops aromatica and Dipterocaropus globosus grew on the more humic soils, along with two other dipterocarps of the ten most important species in terms of basal area; the three non-dipterocarps on this list also grew on the same more humic soils (Davies et al. 2005). The trees are larger than the average in the forest, and only 16% of the trees at least 1 cm diameter at breast height are dipterocarps (Lee et al. 2002).

In the lowland wet tropical West Malesian forests there are huge peat lenses on which these dipterocarps dominate, although not in all the communities (Anderson 1964, 1983; Richards 1996; van Schöll et al. 2008). It has been estimated that Southeast Asian tropical peatlands (mostly Malesian, in fact most Indonesian, all largely made up of dipterocarp peats) occupy about 3/5 of the tropical peatland area, close to 250,000 km2, and about 6.2% of the global peatland area (Page et al. 2011). This peat contains some 68.5 Gt carbon, 77% of the tropical and 11-14% of the global totals for peatlands; these figures do not include estimates of the above-ground biomass (Page et al. 2011). The formation of some peat deposits may have started in the late Pleistocene 40,000 y.a. and the peat is up to 25 m deep (Page et al. 2004, 2012). C storage is long term: In intact forests carbon loss is from recently fixed carbon, while in disturbed forest much older - hundreds to thousands (ca 4,180) of years - carbon is lost (Moore et al. 2013). See also Brown et al. (1993: soil to 1 m only) for biomass estimates, both actual (as impacted by human activities) and potential; other estimates are 84 Gt C in tropical peat, 16 Gt C in southern peats, and as much as 621 Gt C in northern peats (Rydin & Jeglum 2013 and references; Rieley et al. 1997 for other estimates). There are more figures and further discussion in the Clade Asymmetries section.

Recent work emphasizes the great above-ground wood productivity of north Bornean dipterocarp forests, about half as much again when compared with forests in the western Amazon (Ecuador, Peru) that are comparable in soils, precipitation, etc., although solar radiation may be higher in the Bornean forests; dipterocarps were more productive than their non-dipterocarp counterparts in the same foresrs (Banin et al. 2014). This high productivity was despite a much lower amount of phosphorus in the soil in the dipterocarp forests and a C:N ratio about 50% higher (Banin et al. 2014). These are intriguing findings, even if how these figures might relate to underground carbon storage and to the activities of ECM is as yet unclear.

Although these forests may be dominated by dipterocarps, they are often overall highly diverse (e.g. Ashton & Hall 1992; Lee et al. 2002), and in this repect are rather unlike temperate/boreal ECM communities. Moreover, compared with some other very diverse forests in the New World, there are relatively few understory specialists (LaFrankie et al. 2006; Banin et al. 2014).

Shorea robusta (sal) is a gregarious tree that grows in monsoon areas from Pakistan to China, especially in the India-Assam-Myanmar area. Sal forests occupy 115,000 to 120,000 km2 (11.5x106 ha) and make up ca 15% of Indian forests (Tewari 1995). In Africa Monotes is found mostly in areas where ECM Detarieae are common, especially in the Zambezian region and also in Sudanian Brachystegia savanna (White 1983: see map above).

Dipterocarps tend to be mast fruiters, and in the l.t.r.f. of S.W. Sri Lanka and West Malesia all members of the family tend to flower and especially fruit at the same time, apparently in response to climatic changes induced by El Niño events; very uncommon behaviour in the tropics (Sakai et al. 2005: see Fagaceae for temperate mast fruiters). Pigs and other animals, which may be migratory, following the food around, eat practically all the fallen fruits of some populations, yet leave others untouched, and this kind of predator satiation, the enhanced recruitment of seedlings of untouched populations, may be an advantage of masting behaviour (e.g. Janzen 1974a; Curran & Leighton 2000). There are also invertebrate seed predators, many in the small nanophyid weevil genus Damnux, and these can destroy 60-100% of the seed crop (Lyal & Curran 2003). Visser et al. (2011) suggest situations in which masting behaviour could evolve, and the ECM habit of the family has also been implicated in its phenological behaviour and/or predator satiation (Ashton 1982, 2002).

Pollination Biology & Seed Dispersal. Pollination of species of Shorea section Mutica and of other dipterocarps in Sarawak is by chrysomelid beetles and especially curculionids (weevils); in Peninsula Malaysia species of section Mutica are apparently pollinated by thrips (Sakai et al. 1999a; Corlett 2004 for a summary). The pollinators are affected by the synchronized flowering common in the family (Sakai et al. 2005: see above).

Fruit dispersal is predominantly by wind; it is the fallen fruits that are eaten by the mammalian seed predators.

Dipterocarpaceae apparently lack parasitic rust fungi (Uredinales), unlike many other ECM groups (Malloch et al. 1980); this observation should be confirmed - or not - for other members of this clade.

Plant-Animal Interactions. Hemipteran coccoid Beesonidae form distinctive galls on Dipterocarpoideae, although details of the association are poorly known (Gullan et al. 2005).

Economic Importance. Dipterocarpoideae, with their long, straight and clean boles and gregarious habits, are a major source of commercial hardwood. In the mid 1980s they comprised 25% of the world trade in tropical hardwoods, and 80% of that was made up by timber from Shorea. Furthermore, both oleoresins and hard resins (dammar) are collected from a number of Dipterocarpoideae, and dammar may be converted into oil deposits in Malesia (Rust et al. 2010 for references). Dipterocarpoideae are also a source of lac (exudate produced by Coccoidea), butter fat from the fruits, etc. (Ashton 1982; Smits 1994 and references; Lambert et al. 2013 for the resins).

Chemistry, Morphology, etc. Bergenin, a derivative of gallic
acid, is widespread. Stilbenoids, resveratrol and relatives, are common in Dipterocarpaceae (Wibowo et al. 2011), but I do not know if there is any systematic significance in this.

The stipules of Stemonoporus
are extremely caducous. The calyx in many Shoreeae is
imbricate in fruit, while the corolla is basally connate in many Dipterocarpeae. Dipterocarpus
has vascular bundles in the inner integument.

For additional information on Monotoideae see
Catalina Londoño et al. (1995) and Morton (1995). For additional information about Pakaraimaea, see Maguire et al. (1977) and Maguire and Ashton (1980). For other information, see Ashton (1982, 2002), both general, Gottwald and Parameswaran (1966: wood anatomy), and Kocyan (2005: floral development).

Chemistry, Morphology, etc. For general information about this family pair, see Nickrent (2007). Understanding any synapomorphies for the clade depend on more detailed knowledge of all aspects of the poorly-known Muntingiaceae in particular.

Cytinaceae are echlorophyllous parasites with racemose, sometimes capitate, inflorescences in which the individual flowers are moderately sized and easy to make out. The more or less spreading basally connate perianth is in a single whorl, the stamens are extrorse (staminate flowers) and the style is quite long and is expanded towards the apex (carpellate flowers).

Evolution.Ecology.Cytinus is quite often parasitic on Cistaceae (same order!) in the Mediterranean region, but on a variety of non-Malvalean families, perhaps especially Asteraceae, in Africa (Smythies & Burgoyne 2010). In the Mediterranean, endomycorrhizae from the hosts may also be found in tissues of the parasite, although the physiological significance of this is unclear (de Vega et al. 2010, 2011a, c.f. Brundrett 2011). The American Bdallophytum is most commonly found on species of Bursera (Alvarado-Cárdenas et al. 2009).

Pollination Biology & Seed Dispersal. Pollination of Cytinus hypocistus is by ants, other members of the genus are pollinated by other insects, mammals, and birds (de Vega et al. 2009; Smythies & Burgoyne 2010; Johnson et al. 2011b). De Vega and Herrera (2013) suggested that yeasts transported from flower to flower by ants increased fructose and decreased sucrose concentration of the nectar, but the effect of this on pollination is unclear.

The seeds become embedded in mucilaginous material derived from the placentae and funicles (Nickrent 2007), and seeds of Cytinus hypocistis are ingested and dispersed by the tenebrionid beetle Pimelia costata (de Vega et al. 2011b).

Chemistry, Morphology, etc. Harms (1935a) reported a nectary at the base of the style and the staminal
tube of Cytinus. The outer integument, when present,
is much reduced. The seeds of both genera have a blunt projection at both ends (Alvarado-Cárdenas et al. 2009; de Vega et al. 2011).

For general information see the Parasitic Plants website (Nickrent 1998 onwards) and also Heide-Jørgensen (2008); see also Hegnauer in Meijer (1997) for some chemistry, Guzowska (1964) for ovules, embryology, etc., de Vega et al. (2008) for population differentiation in the western Mediterranean, and de Vega et al. (2007) for the anatomy of the endophytic portion of the host. For a monograph of Bdallophytum, see Alvarado-Cárdenas et al. (2009).

Muntingiaceae can be recognised by their two-ranked,
toothed, leaf blades with asymmetric bases and heteromorphic stipule-like prophylls. Their flowers are in extra-axillary
fascicles, the calyx is valvate, the corolla shortly clawed and crumpled in
bud, and the stamens are numerous.

Evolution.Divergence & Distribution. Some characters of Muntingiaceae (lack of stipules; pits not vestured) might suggest that the family may be rather basal in Malvales; characters of the young secondary tissue of Muntingia, such as widely flaring rays, stratified phloem, etc., are like those of most other Malvales.

Chemistry, Morphology, etc. Although Muntingiaceae appear to have stipules, this may not to be the case. Dicraspidia has strikingly
asymmetric prophylls; on the adaxial side of the branch they are orbicular,
foliaceous and persistent, while on the abaxial side they are linear, thin and caducous. In Muntingia
only an adaxial prophyll is present, and it is narrow (Karima Gaafar, pers. comm.: the situation in Neotessmannia is unknown). Sensarma (1957) suggested that the nodes of Muntingia are trilacunar, he interpreted the prophyll as a stipule, nevertheless, nodes indeed appear to be trilacunar. Given that stipules are common in Malvales, their apparent absence in Muntingiaceae needs to be clarified.

Muntingia has a superior,
ovary, caducous calyx, and pendulous placentae, the two other genera have inferior ovaries,
laminar placentation, and a persistent calyx (?: Neotessmannia). Muntingia has erect uniseriate hairs in addition to its tufted hairs. Stamens, etc., are borne on a massive, almost disc-like structure towards the inside of which are dense hairs; the inner side of this disc as it faces the ovary seems to be nectariferous.

Some information is taken from Benn and Lemke (1991) and Venkata Rao (1952a); the
latter suggested that there were glandular, nectar-secreting hairs in Muntingia, but the
hairs seem eglandular to me. Bayer (2002) gives a general account of the family. For wood anatomy, see Gasson (1996), for carpel
orientation, see Ronse Decraene (1992), and for anatomy, see Carlquist (2005a). I am grateful to Lucia Lohmann for sending me material of Muntingia.

Fossils placed in the family are considerably older. Wood attributable to Malvaceae is known from the late Maastrichtian (Cretaceous) ca 68 m.y.a.; it has simple perforation plates in radial multiples and storied wood, but tile cells were not reported (Wheeler et al. 1994). Malvaceous wood (Bombacoxylon) has also been found in Campanian sediments in Texas ca 75 m.y. old (Wheeler & Lehman 2000).

Age. The age of this clade, or more particularly, a major part of this clade (core Malvoideae, inc. Uladendron), has been estimated at (58-)47, 45(-43) m.y. (Koopman & Baum 2008).

Leaves named as Malvaciphyllum macondicus, found in sediments 60-58 m.y. old from Cérrejon, Colombia, have been placed in Malvoideae (Carvalho et al. 2011). No mention is made of hairs of this fossil, but pollen of Bombacacidites was common in the rocks (Carvalho et al. 2011).

Age. Pollen attributed to Bombacoideae (Bombacacidites) has been found in deposits 69-65 m.y. old (Krutzsch 1989; Pfeil et al. 2002 for references).

Synonymy: Bombacaceae Kunth, nom. cons.

Malvaceae are usually readily recognisable even when
sterile by the combination of fibrous bark, alternate, stipulate leaves with
toothed margins, ± palmate venation, and stellate to lepidote indumentum. Mucilage is common. The flowers and fruits are also
distinguishable by a combination of characters. The flowers often have a valvate, connate calyx with a nectary at
the base inside and a contorted corolla; the stamens are often numerous and
variously connate and/or fasciculate. The inside wall of the fruit and/or the surface of the seed is often
hairy.

Some ex-Sterculiaceae - both the
plant in general and the fruit in particular - can look like Euphorbiaceae. Leptonychia
is often confused with that family.

Evolution.Divergence & Distribution. For the early Caenozoic fossil history of Craigia (Tilioideae), see Manchester et al. (2009); Reevesia (Helicteroideae), now East Asian, is known from throughout the North Hemisphere in the early Caenozoic (Ferguson et al. 1997).

Taxa at the nodes at the base of the [Malvoideae + Bombacoideae] clade are likely to have been neotropical (Baum et al. 2004; Nyffeler et al. 2005). Baum et al. (2008: q.v. for dates), discuss the biogeograophy of Malveae. Le Péchon et al. (2010) found that Dombeyoideae had colonized the Mascarenes more than once - and had also acquired dioecy in parallel. Kokia, endemic to Hawaii, is sister to the African Gossypioides; the two diverged ca 12 m.y.b.p. (Seelanan et al. 1997; see Keeley & Funk 2011 for a list of Hawaiin endemics). Nototriche (Malvoideae) is a remarkable genus of dwarfed plants growing in the high Andes; the flowers are epiphyllous, and there is considerable variation in leaf shape.

For the evolution of extra-floral nectaries in Byttneria, see Weber and Agrawal (2014).

Ecology & Physiology. Bombacoideae are an important component of neotropical seasonally dry tropical forest and Amazonian forests in general, being both speciose and having a disproportionally high number of common species among individuals with stems at least 10 cm across (Pennington et al. 2009; ter Steege et al. 2013).

Pollination Biology. In most Malvaceae studied the nectary is made up of carpets of multicellular glandular hairs; the same morphology even occurs in the foliar extrafloral nectaries in Triumfetta, etc. (for nectary physiology, etc., see Sawidis et al. 1989; Vogel (2000 and references; Leitão et al. 2005). The nectaries that provide rewards for pollinators are commonly found on the
inside of the calyx and the corolla is fused at the
base and the broad petal lobes are more or less clawed. This leaves a space through which the pollinator can get at the nectar. Thus access to the nectar is permitted to a pollinator probing the center of the flower; if the corolla were completely connate there would be no easy way for the pollinator to reach the nectar while simultaneously pollinating the flower (Vogel 2000). Overall there is considerable variation in nectary - and staminodium - position and type in the family. Nectaries are borne on the petals in e.g. Grewia and
Luehea and on the androgynophore (and leaf!) in e.g. Triumfetta (all Grewioideae: Leitão et al. 2005).

Byttnerioideae, especially Byttnerieae and Theobromateae, have remarkably complex if sometimes quite tiny
"basket" flowers that are pollinated by small flies and the like (Vogel 2000; Westerkamp et al. 2006; Whitlock & Hale 2011). The petal often has a concave basal portion more or less enclosing the rest of the flower while the limb of the petal may dangle and twist in the wind, as in Abroma; the prominent staminodia are opposite the sepals. Young et al. (1984) suggested somewhat hesitantly that there might be nectar-secreting stomata on the limb and the adaxial base of the petal in Theobromateae, but this report should be confirmed. Buzz pollination occurs in Byttnerioideae-Lasiopetaleae (Vogel 2000).

For pollination in Bombacoideae, see Janka et al. (2008) and references; bat pollination is very common there, although reconstructions suggest that bat pollination evolved before bates... (Fleming et al. 2009; Hernandéz & Magallón 2015). The flowers of Helicteres isora (Helicteroideae), some species of Pavonia (Malvoideae), and the remarkable Chiranthodendron pentadactylon, the aptly-named devil's hand, refering to the five-branched androecium, are monosymmetric, but I do not know the plane of symmetry.

One of the most spectacular examples of secondary pollen presentation I have seen was in a species of Dombeya (Malvaceae), a genus in which I never expected to see such a pollination mechanism; the pollen was attached to the staminodes, where it made a striking colour contrast with the rest of the flower. The pollen can also be presented on the tips of the petals in Dombeya (Prenner 2002), and the genus would clearly repay further work from this point of view.

The pattern of evolution of dioecy in Dombeya, certainly paraphyletic, in the Mascarenes and its dispersal between Madagascar, the Mascarenes and Africa is complex (Le Péchon et al. 2009). There seem to have been four colonizations of the Mascarenes, with at least three acquisitions of dioecy (Le Péchon et al. 2010; see also Skema 2012).

Plant-Animal Interactions. Caterpillars of the nymphalid Acraea are quite commonly found on members of Malvaceae, as are members of Lycaeninae (Fielder 1995). Acanthoscelides, whose larvae eat seeds, are bruchids (Chrysomeloidea-Bruchidae/Bruchinae) that have diversified on Malvaceae s.l., esp. on Malvoideae, more than on other groups outside their primary hosts, members of Fabaceae (Kergoat et al. 2005). Seed-eating bugs of the Hemiptera-Lygaeidae-Oxycareninae are also concentrated on Malvoideae (Slater 1976).

Bacterial/Fungal Associations.Tilia is ectomycorrhizal, and some species are associated with truffels, the ascomycete Tuber.

Genes & Genomes. In addition to general genome duplication events, e.g. the genome triplication of the core eudicots (Vekemans et al. 2012), in the lineage leading to Gossypium (Malvoideae) genes duplicated, and then triplicated after its divergence from Cacao (Byttnerioideae) - in total a 30-36-fold duplication within angiosperms (Paterson et al. 2012). Diversification and molecular evolution in Hibisceae pick up almost together (Baum et al. 2002, 2004), while Andreasen and Baldwin (2001) noted that the rate of molecular evolution of 18S–26S nuclear ribosomal DNA in annual Sidalcea was faster than that in the perennials.

Economic Importance. For the domestication of cotton (Gossypium barbadense), see Dillehay et al. (2007); for the evolution of cotton fibres, see Paterson et al. (2012 and references).

Chemistry, Morphology, etc. The pentacyclic systems in the 4-pyridones and 4-quinolines seem "originate from a polyunsaturated sphingolipid-like compound with a benzoic acid starter unit" (Erwin et al. 2014: p. 361). Tile cells are best observed in radial
section; they are of two or three main types (Manchester & Miller 1978; Carlquist 1988b; Tang et al. 2005b). Any correlation of tile cell "type" with phylogeny awaits a more completely resolved tree, thus the Durio type occurs in both Malvoideae and Byttnerioideae. Vestured pitting is
reported, but probably incorrectly, from Schoutenia and Ochroma
(Jansen et al. 2000a).

Carvalho et al. (2011) discuss leaf venation in the family in considerable detail; additional apomorphies for Malvoideae, at least, may result from such studies. Several taxa have palmate
leaves. In Brachychiton and Adansonia
there is comparable variation within a flush - the first leaf/leaves have a
very short petiole and long, narrow ?phyllode, while later leaves are palmate;
any intermediates have winged petioles and a few leaflets.

For a discussion of the various kinds of extrafloral nectaries in Triumfetta, see Letãio et al. (2005).

The inflorescence in most Malvaceae is made up of "bicolor units" - a terminal flower with three bracts, two of which may subtend cymose part inflorescences with normal bracteole number and arrangement and the third subtends nothing. The epicalyx seems to be made up of these three bracts, and so a flower with an epicalyx represents a highly reduced "bicolor unit" (Bayer 1999); it has evolved several times in the family. Although the inflorescence of Sterculioideae seems to be very differently constructed from that of other Malvaceae, it, too, is composed of much modified bicolor units (Bayer 1999). Nototriche (Malvoideae) has epiphyllous inflorescences.

For androecial development in Malvaceae s.l. compared to that of other Malvales, see Nandi (1998b) and von Balthazar et al. (2006). Von Balthazar et al. (2006) suggest an interpretation of the androecium of [Malvoideae + Bombacoideae] - and extend their findings to determine the basic androecial structure for Malvaceae as a whole. They propose that the basic androecial structure in Malvaceae is obdiplostemonous, with stamens developing in one or both whorls; anther dehiscence is extrorse. In [Malvoideae + Bombacoideae] each androecial unit consists of an antesepalous primordium with its own vascular supply and which remains sterile (usually). This is flanked on both sides by single primordia, each derived from a separate antepetalous primordium and that gives rise to a sessile, elongated theca. The thecae are supplied by a branch from an antepetalous vascular bundle. The androecial unit thus consists of [half anther + sterile primordium + half anther]. Further details are given by Janka et al. (2008), focussing on Adansonia and relatives. Ceiba pentandra has only five alternisepalous stamens, and these are supplied by branches of the oppositipetalous traces, and these and other taxa linke Fremontodendron are described as have bithecal anthers (Bayer & Kubitzki 2002). For additional details of androecial development in Malvoideae, see Janka (2003) and von Balthazar et al. (2004). For floral morphology and development in Dombeyoideae, see Tang (1998) and Tang et al. (2006). In Grewioideae the stamens may arise from ten or
five (if five, then oppositisepalous) primordia, or from ringwall primordia, and the vascular supply to the stamens is variable in origin (Brunken & Bayer 2005); for more, see Brunken (2003; Brunken & Muellner 2012). Van Heel (1966) and Schönenberger and von Balthazar (2006) also discuss androecial development in Malvaceae s.l. The androecia with numerous stalked, unithecate, staminal units so common in this clade are independently derived in Bombacoideae and Malvoideae (von Balthazar et al. 2006).

Although starchy pollen is common in Malvaceae in the old sense, it is not reported from the old Sterculiaceae; details of variation in the clades recognised here are unclear.

Not only are the carpels of Sterculioideae secondarily free, but in Firmiana they open early in development, exposing the developing seeds on the carpel margins; the ripe carpels with seeds attached are dispersed by wind. However, there is a compitum even in these apocarpous Sterculioideae because of the post-genital connation of the apical parts of the styles (Jenny 1988). The carpels are
usually opposite the corolla, although not infrequently (e.g. Hibiscus, Fremontodendron,
Sterculia) they are opposite the calyx; when there are three carpels, the
median member may be either ad- or abaxial (reports of carpel orientation in
individual taxa may conflict - e.g. Eichler 1878; Ronse Decraene 1992).

Although zig-zag micropyles are common here, some taxa have an unitegmic (exostomal) micropyle, but the micropyle is clearly off-centre, while in taxa like Helicteres the apex of the nucellus is initially exposed but a bistomal, zig-zag micropyle is eventually apparent, but only after fertilization; such variation is connected with the precocious development of the outer integument. Ovules of Pterospermum suberifolium are described as lacking parietal tissue but with a nucellar cap up to 16 cells across (Venkata Rao 1952c). For details of embryology, see e.g. Venkata Rao (1950, 1951: exotegmen of Waltheria palisade, 1952b, 1954), Venkata Rao and Sambasiva Rao (1952), and for the embryology of Eriolaena in the context of embryological variation in Dombeyoideae as a whole, see Tang et al. (2009). Leptonychia has parietal placentation, short fibres
in the exotegmen, but starchy endosperm, while Helicteres is described as having exotestal fibres (González & Cristóbal 1997); Corner (1976) discussed the seeds of Malvaceae in some detail; see his "durian theory" (e.g. Corner 1953) for the evolution of the tropical rainforest.

Phylogeny. Apart from Malvaceae, here in Malvoideae, all
the other families in the old Malvales are highly para- or polyphyletic. For information on relationships in the extended family,
see Alverson et al. (1998, esp. 1999) Bayer et al. (1999), and Nyffeler et al. (2005). [Grewioideae + Byttnerioideae] are probably sister to the rest of the family (see also Soltis et al. 2007a), while Sterculioideae are perhaps sister to the well supported [Malvoideae + Bombacoideae] (Nyffeler et al. 2005). Other relationships between the subfamilies are unclear. However, Dombeyoideae and Tilioideae are sometimes weakly associated (Alverson et al. 1999), but the former may rather be sister to all other taxa in the major polytomy (Nyffeler et al. 2005).

Many taxa in Byttnerioideae have only five stamens, a derived condition, even although developmental work might suggest that the higher numbers may be derived by doubling (Whitlock et al. 2001b; Whitlock & Hale 2011). Whitlock and Hale (2011) found that Byttneria was paraphyletic, with Ayenia embedded in it; growth form was a fairly good indicator of relationships here, while Whitlock et al. (2011) evaluated relationships around Commersonia.

Mortoniodendron is to be included in Tilioideae (Nyffeler et al. 2005).

For relationships within Dombeyoideae, Dombeya certainly being paraphyletic, see Le Péchon et al. (2009, 2010) and Le Péchon and Gigord (2014), focus on Mascarene taxa, Won (2009: to include Corchoropsis) and Skema (2012: focus on the Malagasy taxa). Nesogordonia is morphologically rather out of place here.

Within Helicteroideae, Helictereae (ex Sterculiaceae) are sister to
Durioneae (ex Bombacaceae), the latter being from Sri Lanka, Burma to West Malesia and having
lepidote indumentum and an initially connate epicalyx. The anthers of many Durioneae are
polylocular - see also
Nyffeler and Baum (2000).

Relationships at the base of Malvoideae and Bombacoideae are unclear. Ochroma may be sister to other Bombacoideae; its filaments are connate into a tube. However, it and Patinoa formed a clade with no obvious immediate link with Bombacoideae in some analyses (Alverson et al. 1999; see also Baum et al. 2002, 2004) and the two genera may have to be excluded. Sister to the rest - or almost so - in this whole [Malvoideae + Bombacoideae] area may be things like Fremontodendron, which hybridizes with Chiranthodendron
(both ex Sterculiaceae - C 0), etc., and Quararibea, etc. (ex Bombacaceae), support was weak (Alverson et al. 1999; c.f. Bayer et al. 1999; Baum et al. 2002). Quararibea, etc., are best placed in Malvoideae, while [Ochroma + Patinoa] and Septotheca are unplaced (Baum et al. 2004). Indeed, Baum et al. (2004) suggest that [Fremontodendron + Chiranthodendron] may be sister to the rest of the [Malvoideae + Bombacoideae] area since they lack a 6 bp deletion in a conserved region of the matK gene found in all other members of this clade, however, there is little other evidence for this position.

For groupings within Malvoideae, see La Duke and Doebley (1995: restriction site analysis) and Judd et al. (2002). Within Malveae, Tate et al. (2005) found that presence or absence of an epicalyx correlated very well with two major clades recognizable on analysis of ITS sequence data; a subsequent study using this gene and four others found that Malva, at least, was polyphyletic (García et al. 2009). For relationships within Hibisceae, see Pfeil et al. (2002), Pfeil and Crisp (2005) and Koopman and Baum (2008: Malagasy taxa); generic limits around Hibiscus are especially difficult - s. str. or s. lato?, but Hibiscus should probably include Pavonia, etc. Sida is polyphyletic, as is Abutilon (Donnell et al. 2012). For relationships in Gossypieae, complicated by hybridization, see Seelana et al. (1997).

Classification. For a discussion of groupings in the extended family, Robert Brown's comments over
150 years ago (Brown 1814) on family limits in the Malvales (= Malvaceae here) are a good starting point. Malvaceae + Bombacaceae + Sterculiaceae +
Tiliaceae make a readily recognized and well circumscribed group, yet the clades within it are
mostly difficult to distinguish, even with flowers, so combination seems
sensible (Judd & Manchester 1997; Alverson et al. 1999; Bayer et al.
1999); Cheek (2007), however, opted for dismemberment into ten families.

For a tribal classification of Grewioideae, see Brunken and Muellner (2012). For generic limits around Commersonia, see Whitlock et al. (2011) and associated papers, for those around Hibisacus, see Pfeil and Crisp (2005) and Koopman and Baum (2008), and for generic changes around Dombeya, see Skema (2012) and Le Péchon and Gigord (2014), and for those around Abutilon, see Donnell et al. (2012). Generic limits in Malveae had in the past been based mainly on the number of parts of the epicalyx and their fusion, but fruit characters seem to be more useful features when characterising clades (García et al. 2009).